Rate Coefficient Determinations for the Reaction of Br-Atoms with a Series of Oxygenated VOCs

Abstract:

Bromine atoms are known to be prevalent in marine regions, and to contribute to the ozone budget there. In polar springtime, Br-atom levels can be in the range 10⁷-10⁹ cm^-3 in the marine boundary layer, while values over the open ocean may fall in the 10⁵ ≈ 10⁷ cm^-3 range. It is also known that many VOCs and oxygenated VOCs have oceanic/cryogenic emission sources, and reactions of Br with these (O)VOCs can then play a role in the partitioning of inorganic Br, acting as a sink for reactive Br/BrO. Thus, there is a need to develop a more complete and more reliable database for Br/(O)VOC kinetic data than what is currently available. We have embarked on a relative-rate study of the rate coefficients for reaction of Br-atoms with ≈15 (O)VOCs, including alcohols, ethers, aldehydes, isoprene, other unsaturated compounds, and various multifunctional species. Progress on these rate coefficient determinations, and trends in Br-atom reactivity with organics, will be reported.